SANFORD, Fla. — For more than a year, the Trayvon Martin murder case has ignited protests, death ttravhreats, online campaigns, and become the center of national discussion about race, gun laws and self-defense.

Monday the trial finally starts.

Supporters of George Zimmerman and Martin have waged emotionally charged arguments about the deadly encounter Feb. 26, 2012, in this small southern city. The Internet has buzzed with debates about whether Zimmerman was defending himself against an aggressive teen who had begun pummeling him or whether he had profiled and murdered a black, unarmed 17-year-old.

"This is the second trial of the century as far as central Florida goes," said Dave Sirak, chairman of the Central Florida Media Committee, referring to Case Anthony's as the first. "This trial feels larger than the Casey Anthony trial though because we are seeing international interest right off the top."

His group has been helping coordinate media logistics for the trial for months. Court officials have said they will hold daily drawings to assign 24 courtroom seats to members of the public.

Now, 15 months after the teen's death and in a Seminole County courthouse just 6 miles from where Zimmerman shot Martin, a jury will decide a case in which racial profiling and Florida's self-defense laws are on trial alongside Zimmerman.

Did Zimmerman kill Martin because of his race or was Martin the aggressor and Zimmerman legally defended himself with lethal force?

Jury selection for the televised trial was set to begin Monday.

"Both sides are going to have to be careful in juror selection because the race issues in this case are highly charged," said Randy Reep, a criminal defense attorney and former prosecutor in Jacksonville. "If I was the prosecutor in this case, I would be desiring to have black people or other minorities who have had bad experiences based solely on their 'profileable' characteristics."

Those people, Reep said, are more likely to relate and side with Martin. He added that's a departure from common scenarios because usually defense attorneys want black jurors who they believe are more likely to be distrustful of law enforcement officials.

In this case, defense attorneys will be looking for people who don't believe police enforce rules enough, Reep said.

"The most important thing will be picking a jury that will follow the law, will look at the facts in a fair manner, and that is going to not be sidetracked by the other issues," said Elizabeth Parker, a former prosecutor who is now is now a criminal defense attorney in Palm Beach, Fla. "What is important is what happened that night."

Circuit Judge Debra Nelson, who has already ruled that the 500 potential jurors' identities will remain anonymous, will likely ask those summoned what they know about the case, Parker said. Nelson may later sequester the jurors selected to hear the case.

Zimmerman, who has pleaded not guilty to a second-degree murder charge, is claiming he shot Martin in self-defense. Free on $1 million bond, Zimmerman remains in hiding. Talks of Zimmerman's injuries from the alleged fight, the firing of Sanford's police chief, residents' 911 calls, and court hearings about voice experts have kept the case in media headlines.

Prosecutors plan to argue that Zimmerman, a neighborhood watch volunteer, profiled Martin, wrongly assumed he was a criminal, disregarded a police dispatcher's instructions not to follow the teen, confronted the young man, and killed him.

What the six-person jury deciding Zimmerman's fate rules comes down to several key questions that experts say sit at the crux of the case: Who initiated the confrontation on that dark rainy night in Florida? Whose voice is heard screaming for help on a 911 tape moments before the shooting? And, can prosecutors overcome reasonable doubt without any eyewitnesses to the fight?

"Without eyewitnesses, without somebody saying this is exactly how it happened, it is a circumstantial case," Parker said. "Those are difficult cases for prosecutors. Reasonable doubt is a really high burden."

Still, what is clear is this: At about 7 p.m., Martin, wearing a dark hoodie, bought Skittles and iced tea at a 7-Eleven and then walked back to Retreat at Twin Lakes, a gated community, in Sanford, Fla. He staying with a friend of his father's after being suspended from his high school in Miami for having marijuana residue in a bag.

Five to 10 minutes later, Zimmerman spotted Martin walking in the neighborhood and called police. "We've had some break-ins in my neighborhood, and there's a real suspicious guy," he told a dispatcher. "This guy looks like he's up to no good or he's on drugs or something."

Zimmerman began to follow Martin, remaining on the phone with the officer who later tells Zimmerman he doesn't need to follow Martin. The call continues for a few moments and then Zimmerman says police can call him when they arrive.

Exactly what happened next remains a mystery.

A 911 recording of a resident's call is an important clue. During the person's conversation with a dispatcher, a voice is heard screaming "Help!" The screaming abruptly ends with a loud gunshot.

Zimmerman's lawyer, Mark O'Mara, says the voice on the 911 call belongs to Zimmmerman, who was walking back to his vehicle when Martin punched him out of nowhere.

The two fought, began wrestling on the ground, and Zimmerman says Martin started slamming his head into a concrete sidewalk. Zimmerman then says Martin reached for Zimmerman's gun and that he shot the teen in response.

O'Mara says he's confident that once a jury hears the facts, they will realize the case that's garnered the nation's attention is a straightforward self-defense case.

"My guy was trying to do what he thought was right when he got attacked," O'Mara told USA TODAY. "Trayvon Martin overreacted and got aggressive. That's what happened. Color had nothing to do with that night."

Martin's side of the story will never be fully told. However, a friend claims she was on the phone with Martin before and during the confrontation. In her version, Martin, scared and out of breath from running, unsuccessfully tries to lose Zimmerman. "I hear this old man say, 'What are you doing around here?,' " the girl said in an interview with an assistant state attorney. "Then I could hear the grass."

"The evidence is overwhelming," said Benjamin Crump, an attorney for Martin's family. "Trayvon was yelling and screaming for help, and he was shot and killed by George Zimmerman."

Photos shortly after the confrontation show Zimmerman with several a bloody nose and cuts on his head. An autopsy report says Martin died of a gunshot wound to the chest and had no other injuries.

"Zimmerman wasn't doing anything illegal when he was monitoring Martin," Reep said. "If I was the attorney on this case, I'd want people to remember that there is no indication that Zimmerman was trying to engage Martin."

Without eye witnesses, Reep says he believes Zimmerman will be acquitted.

Prosecutors, however, contend there is enough evidence to prove that Zimmerman murdered Martin.

Assistant State Attorney Bernie de la Rionda said he plans to convince six jury members that Zimmerman acted "imminently dangerous" and demonstrated a "depraved mind without regard for human life" — Florida's definition of second-degree murder.

He may call to the stand residents who called 911 during and after the confrontation, Sanford police officers, and officials from the Florida Department of Law Enforcement.

He may also try to use evidence such as Zimmerman's failed application to become a police officer, his past calls to police and Martin's phone records from the night of the shooting.

Meanwhile, Judge Nelson has already ruled that lawyers can't discuss a toxicology report that shows Martin had marijuana in his system the night of the shooting, Martin's school records, any history of fights, any drug use, or any photos or text messages found on the teen's cellphone. She also said witnesses can't discuss whether they think the charges against Zimmerman are politically motivated.

The case gained national attention when Martin's father, Tracy Martin, aided by an attorney and public relations firm, voiced outrage that the killer of his son had gone free without a trial. Police the night of the shooting detained Zimmerman, questioned him, and released him. State prosecutors initially declined to press charges.

Tracy Martin said he continues to be haunted by the moment he identified his son's dead body on Feb. 27, 2012. He called 911 the morning after the shooting to report his son missing. Soon, he was talking to police officers and looking at a photo of Martin lying dead on the ground.

After learning his son's shooter had not been arrested, Tracy Martin contacted Crump who after some time enlisted the help of a public relations firm.

"If we hadn't gotten involved in this case, I think nobody would have known who Trayvon Martin was," Crump said. "Nobody would have cared about this young black unarmed teenager. His family would not have gotten their day of court. I'm proud to help people get their day in court."

Weeks after Crump got involved, the story look off and the nation focused on the narrative of a young unarmed black teen who was killed while walking home with a bag of Skittles and iced tea. Even President Obama commented saying: "If I had a son, he'd look like Trayvon."

People — fixated on Martin, Zimmerman and Sanford, Fla. — debated about race and stand-your-ground laws, which Zimmerman's attorney early on claimed justified the killing.

Florida's stand-your-ground laws state that a person does not have to retreat in the face of a threat and can use deadly force if fearing danger of death or serious harm.

Following the shooting, the U.S. Commission on Civil Rights announced it would launch a special investigation into how race affects the enforcement of stand-your-ground laws across the nation. Florida Gov. Rick Scott, a Republican, also established a task force to review his state's stand-your-ground law. Martin's parents publicly lobbied for such laws should be amended.

But O'Mara eventually changed his argument to simple self-defense saying Zimmerman could not retreat so the law didn't apply to his case. O'Mara says he hopes jurors will agree but says he's worried jurors will feel pressured to convict given the amount of publicity the case has received.

"This is not a civil rights case," O'Mara said. "We have 45 witnesses who all say George is a peaceful, mellow, non-racist.

Crump disagrees and says a guilty verdict will send a message that racial profiling and discrimination will not be tolerated. "We have to keep fighting to make America live up to its creed of equal justice for us all," he said.

As evidence, Martin supporters point to the firing of Sanford Police Chief Bill Lee, who was let go after the department was strongly criticized for its initial investigation into Martin's death. The teen's parents also settled a wrongful-death settlement with the Twin Lakes Homeowners Association that could have paid $1 million or more.

Despite all the public attention and questions, at the heart of the case is two families who will sit opposite each other in a courtroom every day this summer.

On one side, George Zimmerman's brother, parents and other relatives will listen to lawyers trying to take away their loved one's freedom. Several family members, who have also been in hiding, will have security.

"I'll be attending to support George and to support the truth," George Zimmerman's brother, Robert Zimmerman, told USA TODAY. "This trial will not just exonerate George. It will be an indictment of the people who deceived the public, filed a criminal affidavit and presented half-truths to get someone charged."

Just cross the room, Martin's father and mother, Sybrina Fulton, and close family members will sit and listen to details about how the teen died. Fulton, who has been traveling and doing countless appearances since last year, says she will attend the trial every day.

"I know it's going to be very difficult, but what could be more difficult than us losing our son?" Fulton said. "We want justice, and we want everyone to remain calm."

It's a request she's made over and over again. And it's one, Seminole County Sheriff Donald Eslinger says the more than 18,000 people who have protested in Sanford have abided by. Through all the demonstrations, Eslinger said there hasn't been one arrest or one law broken.

He says he hopes that fact will remain true throughout the trial. Still, his office, with help with other agencies, will have extra security to make sure the court remains functional with all the new foot traffic. About 100 journalists will be in the courthouse. Twenty-four reporters will sit inside the actual proceedings.

In downtown Sanford, city officials have created designated public assembly zones, created emergency plans for the announcement of the verdict, and have increased the number of officer on foot patrol.

However, residents and city leaders acknowledge that even though talk about the case has lessened, most in Sanford want a resolution to the case.

"Everyone is one pins and needles waiting to see what happens," said Sanford Police Chief Cecil Smith.